Heat welded joints between webs of reinforced plastic foil

Abstract

The invention refers to heat weld joints of the type used for adjoining webs of reinforced plastic foil intended for use as stretched ceiling covers. The invention consists in the provision of means at intervals along the heat weld joints for reinforcing same to withstand the influence of heat. The invention also covers a process for the preparation of such reinforced heat weld joints.

What is claimed is: 
     
       1. A cover comprising at least two elongated webs of reinforced plastic foils for use as a stretched ceiling cover with each web having edges extending in the elongated direction of the web and with the surfaces of said webs disposed in generally planar relationship and the elongated edges of said webs disposed in parallel relation, wherein the improvement comprises that the elongated edges of said webs being bent out of the plane of said webs and extending angularly outwardly from the plane of said webs, adjacent said elongated edges on adjacent webs being disposed in contacting relationship and heat welded together along their lengths forming a heat welded joint therebetween, means extending through the outwardly bent portions of said elongated edges of said webs forming the heat welded joint for securing the outwardly bent portions together, and said means positioned at spaced intervals along the length of the joint for reinforcing the joint. 
     
     
       2. A cover, as set forth in claim 1, wherein the reinforcing means being arranged at equally spaced intervals along the length of the heat welded joint. 
     
     
       3. A cover, as set forth in claim 1, wherein the cover comprises at least three said elongated webs of reinforced plastic foils, and said reinforcing means in adjacent heat welded joints being staggered relative to one another in the length direction of said joints. 
     
     
       4. A cover, as set forth in claim 1, wherein said reinforced plastic foils include a reinforcing structure fabric of polyamide fibers subject to heat shrinkage. 
     
     
       5. A cover, as set forth in claim 3, wherein the spaced interval between adjacent reinforcing means along the length of said heat welded joints is 0.3-0.8 times the dimension of the web extending transversely of the length of the heat welded joint. 
     
     
       6. A cover, as set forth in claim 3, wherein said reinforcing means consists of a thread stitched through the portions of adjacent elongated edges of said webs forming the heat welded joint. 
     
     
       7. A cover, as set forth in claim 6, wherein the spaced intervals of said stitched thread reinforcing means extending along the length of said heat welded joint occupies about one-fourth of the length of the joint. 
     
     
       8. A cover, as set forth in claim 6, wherein said reinforcing means extending through said heat welded joint are located intermediate the planar surfaces and the elongated edges of said webs.